The present invention relates to packet communication methods, systems, and computer program products, and, more particularly, to methods, systems, and computer program products for inverse packet multiplexing.
Inverse multiplexing can generally be described as a logical bonding of multiple instances of transmission media to provide greater aggregated bandwidth over a logical path than could otherwise be provided using a single instance of transmission medium. Inverse multiplexing is typically used to create higher bandwidth pipes across a span of network segments whose individual transmission elements cannot support the total end point offered load.
For example, carriers have deployed significant bandwidth capacity in recent years through the construction of long haul and metro optical networks. Concurrently, enterprise networks, often based on Ethernet technology, have steadily increased their bandwidth capabilities from 10 Mb/s to 1 Gb/s. Unfortunately, there has not been a network build-up to link these enterprise networks with the newly deployed carrier facilities. Presently, most of a carrier's customer base is connected through existing outside plant copper pairs. These copper pair spans, however, have technical bandwidth limitations, which can make it difficult to take advantage of the greater bandwidth capabilities of the enterprise networks and/or the carrier's optical networks.
Existing copper transmission technologies are often limited in bandwidth and/or reach. For example, one DSL technology, ITU 991.2 (G.shdsl) provides for logical bonding of multiple copper transmission media; however, the number of physical paths that can be bonded is limited to two. Another DSL technology known as VDSL can support low-end Ethernet transmission speeds, but is limited to a reach of approximately two thousand feet.
FIG. 1 illustrates a network model in which two networks A and B are connected by multiple physical media spans. As shown in FIG. 2, each network has at its interface a network element or node. In the example shown, packets are being transmitted from Node A at Network A to Node B at Network B. One approach to utilizing the multiple spans or links connecting Network A to Network B would be to demultiplex packets across the various links as shown in FIG. 3 on a per-packet basis. Unfortunately, this approach may not be desirable in some cases. Latency may be higher than desirable if there is less offered load than the total available aggregate link bandwidth. By demultiplexing the packets on a per packet basis, the latency incurred is equal to that caused by the active links. That is, the latency for an individual packet will be based on the particular bandwidth for the individual link on which the packet was transmitted. In addition, link bandwidth may be underutilized if only a subset of links is carrying packet traffic.